Factors influencing food intake of rats fed low-protein rations

Meyer, Jerome H.; Hargus, W. A.

doi:10.1152/ajplegacy.1959.197.6.1350

Cited by 62 publications

(13 citation statements)

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Section: Discussionmentioning

confidence: 99%

“…Because of this reciprocal metabolic relationship, the interaction of the protein and energy contents of the diet may influence the feeding behavior. In fact, food intake was depressed in rats fed on a very low or high protein diet (11,12).The present study was undertaken to explore the possible relationship between self-selection of dietary protein and its subsequent utilization in rats with VMH lesions. In further studies on the feeding behavior of rats with VMH lesions, we also studied dietary selection of non-protein energy in response to restricted protein intake and vice versa.…”

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confidence: 98%

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Effects of protein and energy on dietary selection and protein utilization in rats with ventromedial hypothalamic lesions.

Shizuka

Kishi

Inouei

1983

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryThe effect of bilateral destruction of the ventromedial hypothalamus (VMH) on protein and energy intakes was examined in relation to protein utilization. In Experiment 1, rats with VMH lesions were allowed to select protein (either casein or wheat gluten) and energy from two diets containing 70% and 5% protein, respectively. In Experiment 2, they were restricted to 0,100 and 200mgN/day of protein and given free access to protein-free diet. In Experiment 3, they were restricted to 2 and 5g/day of protein-free diet but given 92% protein diet ad libitum. Self-selecting rats with VMH lesions consumed about 100kcal/day regard less of the protein source, in contrast to sham-operated controls which consumed 75kcal/day. They showed increased non-protein energy intake with constant protein consumption resulting in normal protein retention with increased body fat. When protein intake was restricted to 200mgN/ day, energy intake was reduced in animals given diet containing wheat gluten more than in those given diet containing casein, resulting in lower protein utilization. Therefore, food intake depended upon the amount of dietary protein. Rats with VMH lesions showed an exaggerated response to the ratio of protein to energy in the diet and consumed more energy from balanced diet but showed more reduction in food intake than controls in response to diet with an inappropriate ratio of protein to energy. The present study confirmed that the VMH was related to regulation of energy intake but not protein intake. It is suggested that protein intake is regulated in relation to maintenance of body protein in rats with VMH lesions as well as in normal rats. Key Words self-selection, protein restriction, energy restriction, protein utilization, protein intake regulation, VMH lesion Bilateral destruction of the ventromedial hypothalamus (VMH) produces the characteristic symptoms of hyperphagia, hyper-reactivity to palatability of the diet, and hormonal and metabolic alterations associated with enhanced accumulation of body fat (for recent review see (1)). From the symptom of hyperphagia, this locus has been recognized as the "satiety center" and the hypothesis of a dual center of food intake has been established (2).It is well known that both the quality and quantity of protein in the diet affect food intake. Food intake of rats with VMH lesions as well as of intact rats is depressed in response to a diet with excess of a single amino acid (3), with an imbalance of amino acids (3, 4), and with a high protein content (3, 5). Moreover, Rozin (6), Musten et al. (7), and Kishi et al. (8) suggested that the regulations of protein intake and energy intake are different. Anderson et al. (9) concluded from a study on self-selection of diet that regulation of protein intake was normal in both hypothalamic hyperphagic and obese Zucker rats. The mechanism of regulation of protein and amino acid intakes is still unknown, but although direct evidence is still lacking, the VMH is not supposed to be involved.From the nutritional point of vi...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 98%

Effects of protein and energy on dietary selection and protein utilization in rats with ventromedial hypothalamic lesions.

Shizuka

Kishi

Inouei

1983

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…In these circumstances an increase in energy requirement induced by exercise or cold stress increases food intake (Meyer & Hargus, 1959). It is possible that both fatty and lean rats in our experiments restricted their food intake on low-protein diets because of a limited metabolic capacity to support the pattern of protein and lipid (by way of lipoprotein) deposition normal to each phenotype.…”

Section: Vol 36mentioning

confidence: 99%

Regulation of food intake during growth in fatty and lean female Zucker rats given diets of different protein content

Radcliffe¹,

Webster²

1976

Br J Nutr

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I . Food intake, and the rates of protein, lipid and energy deposition during growth were measured for lean and congenitally obese (fatty) female Zucker rats given diets of different protein content ad lib. Six semi-synthetic diets were used, which contained 40, 100, 150, 300, 500 and 700 g casein/kg (diets 40C, IOOC, I~o C , 300C, 5ooC and 700C). 2. Dietary treatments began when the rats were 34 or 35 d old. Collections of urine and faeces were analysed for energy content. The total carcasses of all the rats were analysed individually for protein, lipid and energy.3. In the first experiment, twelve rats of each phenotype were given diets 150C or 300C. Four fatty and four lean rats were killed at 50,66 and 98 d of age. In the second experiment groups of four fatty and four lean rats were given diets 40C, IOOC, 500C and 700C ad lib.until they were killed at 66 d of age. Other groups of fatty rats were pair-fed from 35 to 67 d of age on diets IOOC and 5ooC. Rats were also killed at 24 and 34 d of age to provide initial samples for the comparative slaughter procedure.4. When given food ad lib., fatty and lean rats had identical rates of protein deposition at all ages and for all diets, but lipid and energy deposition were always much greater in the fatty rats. Food intake was also much greater for the fatty rats (except on diet 40C). Differences in food intake and growth rate attributable to diet were most pronounced for the range of diets 40c-150c.5. Fatty rats pair-fed to lean rats deposited less protein but about twice as much energy and lipid as lean rats on the same diets.6. The results are discussed in relation to existing theories of appetite control. It appears that food intake is precisely regulated in the congenitally obese Zucker rat. This regulation is intimately linked with the impetus for protein deposition and the rates of retention of lipid and energy appear to be of no importance in relation to appetite control.Zucker & Zucker (1961) described a strain of rats in which obesity is inherited as a simple, autosomal, recessive gene. Homozygous recessive individuals (fafa, fatty rats) are noticeably fatter than their lean litter-mates by about 3 weeks of age. Individuals carrying one or two normal alleles (Fafa or FaFa, lean rats) are normal in appearance and body composition.Given free access to a diet adequate in all nutrients, the fatty rat has a much higher rate of lipid deposition than a lean rat of the same sex. This is not, however, due to hyperphagia alone. When fatty rats were restricted to a food intake equal to that of lean rats the rate of lipid deposition was 50 % greater in the fatty rats (Bray, York & Swerloff, 1973).The influence of food intake on the rate of protein deposition during growth in fatty and lean Zucker rats is less clear. The rate of protein deposition is undoubtedly much lower in fatty rats when given comparable amounts of food to lean rats. The extent of the difference has been reported to be 67 yo (Bray et al. 1973) or 56 yo (Pullar & Webster, 1974). The results of Bray ...

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“…An attempt by Meyer and Hargus (1959) to increase the food intake of rats fed low-protein diets utilized reduced temperature and forced exercise. That experiment produced the effect of proportionally greater increments in body weight for low-protein than for normal-protein groups due to the failure of normal-protein groups to respond to the changed conditions.…”

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The effect of protein malnourishment and caging on growth and behavior of laboratory mice

Goodrick

1974

Developmental Psychobiology

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Inbred (A/J and C57BL/6J) and hybrid mice were given access to low-or normal-protein diets (4 or 26% casein) at 5 weeks of age and housed 1, 2, or 5 mice per cage. For all groups body weights of mice fed normal-protein diets were greater for groupcaged than for isolated mice, and body weights of mice fed low-protein diets were less for group-caged than for isolated mice. At 15 and 16 weeks of age, mice fed low-protein diets engaged in more exploratory behavior and were less emotional than mice fed normal-protein diets. Mice that were group caged engaged in less exploration and were more emotional than isolated mice. In addition to the major effects of caging and diet on behavior. mode of inheritance was significantly modified.

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Factors influencing food intake of rats fed low-protein rations

Cited by 62 publications

References 2 publications

Effects of protein and energy on dietary selection and protein utilization in rats with ventromedial hypothalamic lesions.

Effects of protein and energy on dietary selection and protein utilization in rats with ventromedial hypothalamic lesions.

Regulation of food intake during growth in fatty and lean female Zucker rats given diets of different protein content

The effect of protein malnourishment and caging on growth and behavior of laboratory mice

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